A persistence and determination in practice. :)
That afternoon I made maybe close to 100 shots of bees on the flowers. Only 5 or 6 came out good enough to be used, at right timing, perfect lens focus and not to bad motion blur.
I was using 150mm lens with 1.4X tele adapter.
Shooting with a 400 mm FF equivalent lens from hand held is a bit tricky. And those bees are moving here and there so fast & quick.